At present, MEMS sensors have been widely applied to various fields in modern life. For example, MEMS tire pressure detectors have been applied to various vehicles, whereas MEMS sound transducer, MEMS gyros or MEMS accelerometers have been applied to various smart phones. There are also many other MEMS sensors applied to smart electronic products required in the Internet of things.
The MEMS sensor usually determines changes in physical quantities (e.g., acceleration, angular velocity, geomagnetism, etc.) through motion of a built-in movable element. When a motion range is overly large, the movable element can suffer damages caused by hitting surrounding structures (e.g., a cover). In the prior art, a stationary stopper has been adopted to stop the movable element from generating excessive movements. However, while withstanding the movable element, the existing stopper can produce enormous impact force and yet provide extremely short stop time so the movable element or the surrounding structures can still be damaged in the stopping process.
In addition, electrostatic interaction can be generated between the existing stopper and the movable element. When the movable element with electric charge is close to the stopper, the stopper will generate an induced charge which interferes with a voltage generated by the movable element during measurement thereby affecting accuracy of the movable element during measurement of physical quantities.